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Date: Sun, 10 Apr 2011 08:29:27 -0700 (PDT)
From: Afflictedd2 <flethuseo@gmail.com>
To: core-user@hadoop.apache.org
Subject: Filtering while mapping or reducing?
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Hi everyone,

I need to add the frequencies of two elements with the same last letter,
however
I don't want single elements in the output of this map reduce. I don't know
where
the filtering of those elements should either be done in the mapping
function or
the reduce function?

For example, if I have the following pairs:

{"f2B"=3D>4,
=C2=A0"f1A"=3D>3,
=C2=A0"f2C"=3D>5,
=C2=A0"f1B"=3D>4,
=C2=A0"f2D"=3D>7,
=C2=A0"f1C"=3D>5,
=C2=A0"f2E"=3D>8,
=C2=A0"f1D"=3D>7,
=C2=A0"f1F"=3D>8,
=C2=A0"f2A"=3D>3}

I want the following pairs out

{"B"=3D>4,
=C2=A0"A"=3D>3,
=C2=A0"C"=3D>5,
=C2=A0"B"=3D>4,
=C2=A0"D"=3D>7,
=C2=A0"C"=3D>5,
=C2=A0"E"=3D>8,
=C2=A0"D"=3D>7,
=C2=A0"F"=3D>8,
=C2=A0"A"=3D>3}

but I don't want E and F in my final result of reduced pairs

{"B"=3D>8,
=C2=A0"A"=3D>6,
=C2=A0"C"=3D>10,
=C2=A0"D"=3D>14,
}
--=20
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